The Rx-7... Unreal.

As some of you know, I just picked up my first FD 2 weekends ago. There have been many struggles along the way. The car likely has a small seal problem (small bubbles, brief white smoke on startup, overpressurized coolant system leakage.) I can handle that, the car is beautiful and I will just work my *** off to raise the money to get it fixed.

The turbos didn't seem to be working properly, as I was only getting 3psi when I performed a boost test at WOT in 3rd. Hmmm, didn't really matter, I mean this thing was still fast as hell. How could this car be any faster? It still snapped my back in my seat and had a mean sounding BOV. (Or so I thought it was the BOV, it was actually just the air escaping the system through a hose, lol) I could hear the turbos spinning, and felt the power. Life was good.

Then, I said... you know what, I'm going to try to determine if there is a boost leek somewhere. I'm an idiot when it comes to the internals of this beautiful machine, but I'll give it a go.

There are some Ultra helpful people on the forum, and I figured with their guidance, I would do what I could to find a leak.

I followed the guide "Troubleshooting Sequential Turbocharger problems" guide, and was pretty overwhelmed. I attempted step one, which was the "Y-Pipe connector hose, (coupling)" After about an hour of dinking around looking for the right tools, I finally got the coupling off, and inspected it. I stretched it, and couldn't find any holes. What a huge disappointment I thought, all of that work and it wasn't cracked! Well, onto the next possible trouble area!





Hmmm... another week passes, and I start talking with a really helpful guy on the forums named rynberg. He walks me through a lot of steps to take, and does a really good job of explaining to my how the system works and what I should be looking for.

I decide to go up to the store and pick up a vacuum tester, just to verify that my stock gauge is working correctly. (rynberg thought that if I was spooling, and hearing a BOV, while blasting me into my seat, it might just be a bad gauge)




I hit the road with my new gauge, hose running in through my window... feeling like an expert rotary mechanic. Because at this point I pretty much am.

I hit the road and try a little spool, and these are my results... 2PSI. Hmm, the gauges seem to match up pretty well with each other too! Looks like the gauges work... there MUST be a leak.

http://www.bentarnowski.com/rx-7/boost/Boost4tloss.MPG

I get home flustered... and say... wthell, I may as well inspect all of the hoses that are in the very front, near the intercooler area. This morning I was doing another test, and was freaking out when my air pump would shut off halfway though a rev. rynberg quickly set me straight, and said this was normal. During the run however, I remembered that my bottom intercooler pipe was shaking at about 4000rpm, like there was some massive air flow in it. (If you look closely at the following video, you can see the tube move as the air flows out of it.)

http://www.bentarnowski.com/rx-7/boost/AirPumpStall.MPG

I decided to check all of the hoses down in this area, and try to find a leak.



After another hour or so of my wonderful mechanical skills, I got all of the hoses off and began to inspect them... and guess what I found!!!



You dirty girl you... running this whole time with such a massive hole on the backside of the pipe! I guess the "Whooosh" I heard was the air leaving the unit! Imagine how cool I feel now thinking back to the times when I "whooshed" at people checking out my car. :P

Soo... what was I to do about this hole? I wanted to make sure that this indeed was the cause of my boost issues... some type of temp solution would be needed for me to trial the car again, and make sure it wasn't something else! (Like a wastegate that was stuck open).

But is there a product that would mend this hole and allow me to blast 10psi down the tube?

Of course there is...

The rest is history...

 

I get her out on the road, and the car is freeeeeaking nuts. The portable vac gauge stops at 10psi, so I'm not sure on my readings, but my autometer seemed to give me back a 11/12-4-10 pattern.

I think this is the first time the 2ndary turbo has run in a few years.

I have never even dreamed that a car could go so fast.

Now, my questions for the wonderful people of these forums. What parts should I purchase to replace the hoses that come from the bottom/top of the intercooler, and connect to the engine? Is that the "greddy y-pipe" that I hear everybody talking about? The hose that had the wholes in it was on the backside of the bottom most hose that first leaves the base of the intercooler.

I'm aware that the ducktape is going to melt away very soon under extreme engine temps, and I plan on getting a replacement ASAP.

Secondly, the car has a downpipe, HKS exhaust, and duel Apex air intakes. Stock ECU, stock everything else. I do not want to damage the engine with 12psi spikes. Is there anything I can do, short of getting a computer, to prevent my system from overspiking? Considering the fact that the prim and especially the 2ndary turbo have not seen much action over the last few years, is there anything I should do to them to make sure they are able to run?

Thank you in advance. Again, you guys are great. I'm very grateful for all of the PM's and help that I have received from you. Special thanks go out to rynberg.



See you all on the road!

-Rotary for the win!

 

you can find replacement stock hoses in the 3rd gen for sale section, their are tons of them lying in peoples garages from single/ other intercooler conversions. Hell ive even got one laying in my garage :P

or you can get a stock hose replacement with silicon kit from stores like www.rx7store.net

as far as the spiking, you could port the wastegate (hell of a job) or mess around with a bleeder boost controller. If it were my car though i would pull the stock boost pill out of the line to the 1st turbos wastegate and drill out the hole (in extremely small incriments). Ive never had to troubleshoot spiking on a fd though so somone might have a better solution.

 

heres the direct link if you have trouble finding it.

http://www.rx7store.net/index.asp?Pa...ROD&ProdID=430

 

Congrats on the fix! sorta... now you gotta fix your weird boost pattern. Welcome to the wonderfull world of FD3S

 

Great Post. Wouldn't you know, duct tape. Hats off to rynberg.

 

That's still kind of a low transition. Should be more like 11-8-11 or so....

 

Congrats on the self-fix. It's really not that hard to do, just time consuming. It's better to be slow working on it when starting out than to try and hurry and break parts.

I would go right ahead and order new turbo control solenoids. Solve many transition problems, and if they aren't bad yet they will be soon. $110 well invested if you like boost.

Then look for popped/leaky hoses in that area when you install them, or consider doing a full or at least partial vacuum hose job. If you do a partial hose job, change all hoses going to/from the pressure chamber, vacuum chamber, charge control solenoid, charge relief solenoid, turbo control solenoids, and the wastegate/precontrol solenoid pair. That will ensure you get boost and shouldn't be near as difficult as doing the whole rats nest.

As for spikes, you can change the wastegate boost pill to something a Holley carb jet of a larger orifice size. Or install a manual boost controller. In any case, buy the 94 octane if you can get it and don't hammer the car in cool weather.

Dave

 

gj on the fix man. i feel exactyly like you do right now. ever since i bought my car there has always been turbo issues so i never felt that 10-8-10. i got my good friend Aleem (trini in the forums) to do a non seq conversion and fix what ever else that wasn eeded since i dont really know much well i was at his house every day helping him a bit and learning and such so i have a pretty good idea etc etc. but omfg when i drove that car and felt that 11psi all the way from 3k rpms to redline.... its amazing. no transition for me any more... jsut straight 10psi all the way through gotta love our cars

 

I got my hoses from http://www.boostcontroller.com/ just had to measuer the old hoses and figure out what i needed, was really easy. As mentioned above maual bost contorler, or you can do the pettit computer its cheaper then the PFC, check out some of there stuff http://www.pettitracing.com/flash.htm
Duck-tape solves all aliments LOL

 

Regarding the low transition, do the KOKO test. If the turbo control actuator doesn't positively move out with key on, and in with key off, at least one of those solenoids is sticking and needs replaced. Search for KOKO on the fd3s.net website for the procedure.

Dave

 

what kind of camera is that

 

BTW, thanks for taking pics. I know I'll be linking to this thread anytime someone asks how to find a boost leak.

Dave

 

I've got a new replacement coming in from scratchjunkie. I have decided to keep the stock pipes untill I upgrade the intercooler and such.

The boost spikes have stopped, and it was leveling out around 9-10 psi. That could be because the duck tape is starting to melt. Who needs an ECU upgrade when you can just fix the problem with half melted ducktape? lol

On a more serious note, I'll check into spike issues after I get the new part on.

I'm just happy for a somewhat functional boost pattern!

-Rotary for the win

 

I burst out laughing when i saw the duct tape "fix"

But, myself, i've done some getto rigging... see ------> https://www.rx7club.com/3rd-generation-specific-1993-2002-16/im-stumped-%2Avid%2A-427770/

 

Good job on finding that. I have had that same hose split 2 times and both times it took me forever to figure out the problem. Also both times I fixed it exactly the same way for about a month until finding a replacement. Duct tape is the best! Now I have the hard pipes that come with the Greddy elbow so I wont have that hose split to worry about any more.
I think you can get the Greddy elbow both with and without the pipes, but it is probably worth getting it with the pipes as those hoses are $95 from Mazda (at least my local dealer) and any used one you get is not going to last much longer any way.

 

i just said, ohelll no, when i saw the duct tape, but it works, and is proven so gj and good fix^^.